<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
</head>
<body>
<script>
    function Animal(){
        console.log(typeof  Person.prototype);
    }
    function Person()
    {
        console.log(typeof  Person.prototype);
    }
    function Student() {
        console.log(typeof  Person.prototype);
    }
    function Person(a){
        this.a = a;
    }
    Person.prototype.sayHello = function(){
        console.log('a');
    }
    function Person(s){
        this.s = s;
    }
    Person.prototype.sayHello = function(){
        console.log('s');
    }
    function Person(p){
        this.p = p;
    }
    Person.prototype.sayHello = function(){
        console.log('p');
    }
    var s = new Person(p);
    var p = new Person(a);
    s.sayHello();
    p.sayHello();
    </script>
</body>
</html>